Commit a717943d authored by Vincent Donnefort's avatar Vincent Donnefort Committed by Steven Rostedt (Google)
Browse files

tracing: Check for undefined symbols in simple_ring_buffer 

The simple_ring_buffer implementation must remain simple enough to be
used by the pKVM hypervisor. Prevent the object build if unresolved
symbols are found.

Link: https://patch.msgid.link/20260309162516.2623589-19-vdonnefort@google.com


Reviewed-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: default avatarVincent Donnefort <vdonnefort@google.com>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 63592308

kernel/trace/Makefile

+16 −0
Original line number Diff line number Diff line
@@ -132,4 +132,20 @@ obj-$(CONFIG_TRACE_REMOTE) += trace_remote.o 
obj-$(CONFIG_SIMPLE_RING_BUFFER) += simple_ring_buffer.o

obj-$(CONFIG_TRACE_REMOTE_TEST) += remote_test.o



#

# simple_ring_buffer is used by the pKVM hypervisor which does not have access

# to all kernel symbols. Fail the build if forbidden symbols are found.

#

UNDEFINED_ALLOWLIST := memset alt_cb_patch_nops __x86 __ubsan __asan __kasan __gcov __aeabi_unwind

UNDEFINED_ALLOWLIST += __stack_chk_fail stackleak_track_stack __ref_stack __sanitizer

UNDEFINED_ALLOWLIST := $(addprefix -e , $(UNDEFINED_ALLOWLIST))



quiet_cmd_check_undefined = NM      $<

      cmd_check_undefined = test -z "`$(NM) -u $< | grep -v $(UNDEFINED_ALLOWLIST)`"



$(obj)/%.o.checked: $(obj)/%.o FORCE

	$(call if_changed,check_undefined)



always-$(CONFIG_SIMPLE_RING_BUFFER) += simple_ring_buffer.o.checked



libftrace-y := ftrace.o